1. Field of the Invention
This invention relates to an image pickup lens and an image pickup apparatus and can be applied suitably to an image pickup lens ready, for example, for a wide angle of view and a small-sized image pickup apparatus such as a digital still camera or a portable telephone set with a camera in which a solid-state image pickup element such as a CCD (Charge Coupled Device) element or a CMOS (Complementary Metal Oxide Semiconductor) element is incorporated.
2. Description of the Related Art
In related art, a portable telephone set with a camera and a digital still camera which incorporate an image pickup apparatus in which a solid-state image pickup element such as a CCD element or a CMOS element is used are known. For such an image pickup apparatus, further reduction in size is demanded, and also as an image pickup lens incorporated in the image pickup apparatus, an image pickup lens having a reduced size and a reduced overall length is demanded.
Also widening of the angle is simultaneously demanded for the image pickup lens, and an image pickup lens of a reduced focal length is demanded together with a demand for miniaturization.
Further, in recent years, also in a small-sized image pickup apparatus like a portable telephone set with a camera, increase of the number of pixels of an image pickup element is advancing together with miniaturization, and a model which incorporates a high pixel number image pickup element of a megapixel resolution or more has become popularized.
Simultaneously, also widening of the angle of the image pickup lens is demanded, and therefore, also for an image pickup lens for an image pickup apparatus incorporated in small-sized image pickup equipment, a high lens performance ready for such a high pixel number image pickup element is demanded. As such a small-sized high-performance image pickup lens as just described, a demand for an image pickup lens having three or more lenses is increasing. Such an image pickup lens as just described is disclosed, for example, in Japanese Patent Laid-Open No. 2007-155868 (hereinafter referred to as Patent Document 1), Japanese Patent Laid-Open No. 2005-292559 (hereinafter referred to as Patent Document 2), Japanese Patent Laid-Open No. 2004-341512 (hereinafter referred to as Patent Document 3) and Japanese Patent Laid-Open No. 2008-33376 (hereinafter referred to as Patent Document 4).